There are already many uses for hub carriers in the automotive sector. Within the wheel bearing arrangement, it is the function of a hub carrier to connect the wheel bearing firmly to the chassis or the body of a commercial vehicle, a passenger vehicle or a motorcycle.
In the production of modern motor vehicles, there is increasing emphasis on subassemblies that are already pre-installed, and these can generally be connected or attached to the vehicle or installed thereon in a relatively simple manner. The same applies to the hub carrier, into which it is generally possible to integrate a wheel bearing unit and which is fitted together with the latter. In this arrangement, the wheel bearing unit is connected to a component that transmits drive torque. A component of this kind could be a shaft or a joint bell, which ensures the desired positive engagement for torque transmission by means of longitudinal splines or end toothing, for example.
However, it is precisely these interfaces, which should be made as simple as possible for the production process that can prove problematic when it comes to environmental influences during operation. Thus, the mechanical interface mentioned is often situated in the vicinity of a gear-side (or alternatively vehicle-side) seal arrangement of the wheel bearing and is protected only inadequately against environmental influences.
US 2002/0049091 A1 has disclosed a wheel bearing unit in which the wheel bearing is screwed to the joint bell by way of a flat rolled collar and can be put into operation by means of longitudinal splines. The gear-side seal arrangement of the double-row angular ball bearing is formed by a cartridge seal, which achieves an enhanced sealing action in comparison with seal arrangements that have a sealing and a centrifugal ring.
The teaching of the existing prior art consequently aims to enhance the sealing action of the gear-side seal arrangement in order to avoid the ingress of foreign particles into the wheel bearing, but this can lead to significant reductions in the life of the wheel bearing.
DE 92 03 402 has disclosed a bearing seal for motor vehicles which, as part of a wheel-side seal arrangement, has a ring element which is fastened to the outer ring of the wheel bearing and allows dirt particles to be carried away circumferentially.
Fundamentally, there is a similar problem with the wheel-side seal arrangement, just as with the gear-side seal arrangement, but the proximity and size of the rim and also of the brake disk ensures that there is already very good shielding from environmental influences, similar to that with a labyrinth seal. The problem is all the greater in the case of the gear-side seal arrangement, on which the demands are very great.
Moreover, it must be stressed that a measure aimed at enhancing the sealing action of one of the two seal arrangements generally leads to an increased frictional torque in the seal, more specifically at the sealing lips thereof, and hence inevitably leads to increased fuel consumption.